The Eungella Biodiversity Study: Filling the Knowledge Gap
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THE EUNGELLA BIODIVERSITY STUDY: FILLING THE KNOWLEDGE GAP ASHTON, L. A.1,2, LEACH, E. C.2, ODELL, E. H.2, McDONALD, W. J. F.3, ARVIDSSON, D.4 & KITCHING, R. L.2 The rainforest of the Eungella massif has long been recognised as biologically unique: a centre of local endemism and an overlap zone with biota from both the tropical rainforests of north Queensland and sub-tropical elements from further south. We set out to study the rainforest biodiversity of Eungella National Park, and to collect data which would allow us to make predictions on how the fauna and flora of this area may respond to future climate change. Along an elevational gradient, a number of abiotic factors shift, including temperature, humidity and soil chemical properties. The Eungella Biodiversity Project was predicated on the use of an elevational gradient to understand how bio logical communities shift currently with climate, across elevation, in order to predict how this rainforest will respond to future climate change. We established permanent study plots along this elevational gradient and col- lected data on a range of groups including plants, moths, dragonflies, ants, snails and birds. Here, we give some background on the project and describe the botanic and environmental characteristics of the Eungella National Park elevational gradient. Keywords: elevational gradient, microclimate, soils, vegetation 1 School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong 2 Environmental Futures Research Institute, Griffith University, Brisbane, Queensland, Australia 3 Queensland Herbarium, Mt Coot-tha Road, Toowong, Queensland, Australia 4 Brisbane Botanic Gardens, Mt Coot-tha Road, Toowong, Queensland, Australia INTRODUCTION agricultural land, and climate change (Mittermeier The rainforests of the Eungella region are truly sp ecial. et al., 1998; Sodhi et al., 2010; Corlett, 2012). Over This is the largest area of rainforest between the Wet the course of the next century, climate change may Tropics to the north and the subtropical forests of the well exceed the ability of many species to adapt in Queensland/NSW Border Ranges to the south. Despite situ (Mantyka-Pringle et al., 2012). Eungella’s unique characteristics, long recognised by In the Australian context, multi-species, broad- ecologists, botanists and geologists, there have been leaved rainforests are scattered in moist pockets along few (if any) large-scale inventories of the region’s the eastern seaboard from Tasmania to the tip of Cape biodiversity. Most of the area’s uniqueness has been York (Webb & Tracey, 1981; ABARES, 2016). These inferred from opportunistic, taxonomically inspired rainforest patches represent post-glacial remnants collecting, often, ironically, as a waypoint as scientists and, at the time of European invasion of Australia, based further south head for the biological riches of the covered about 43,500 km2 (Stork et al., 2008). About Wet Tropics further north. Only one short article has 70% (ca. 30,000 km2) of this modest area remains discussed the special nature of the Eungella biota in after clearing for agriculture (Stork et al., 2008; general (Winter & McDonald, 1986). ABARES, 2016). Nevertheless, this small remain- Understanding the driving forces that shape bio- ing area may well hold more than 50% of Australia’s diversity is imperative if we are to make informed terres trial biodiversity (Stork et al., 2008). management decisions, especially in a time of rapid During the 20th century, from 1914 onwards, ecological change. Much of the world’s bio diversity is increasing areas of remnant rainforests have been pro- held in rainforests which cover only 7% of the world’s tected. Currently, nationally, an estimated 1.749 million land surface but contain half the world’s biodiversity hectares is located in national parks (48.5% of the total (Myers, 1984; Wilson, 1988). Many rainforests are rainforest estate). A further 26% remains in private experiencing rapid diversity loss, driven by anthro- hands and 8% is leasehold. The remaining 17.5% is pogenic forces including logging, conversion to located in various ‘minor’ tenures (ABARES, 2016). 11 12 PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND In Queensland, designation of ‘rainforest’ national parks are only possible if there is higher eleva tion habitat began in 1908 when Witches’ Falls National Park on available. In addition, there are several other threats Mount Tamborine was declared. This was followed in to the biodiversity of Eungella, including the effects of 1915 by declaration of the very much larger Lamington fragmentation, encroaching forest fires (Hines et al., National Park (Jarrott, 1990). Most of the southern sub- this issue) and introduced species, which may act syner- tropical rainforests achieved World Heritage status in gistically to increase further the vulnerability and 1986 (extended in 1994) (Cavanaugh et al., 2010). The functioning of the Eungella ecosystems. northern ‘wet tropical’ rain forest was awarded similar In 2004, a multidisciplinary biodiversity survey status in 1988 (Valentine & Hill, 2008). was carried out along an elevational gradient in the The reserve now known as Eungella National Park subtropical rainforests of Lamington National Park was established in a piecemeal fashon from 1936 in South East Queensland. Insects and their relatives onwards, being amalgamated into a single-named (the ‘arthropods’) and plants were the primary focus of park in 1961 (Ogilvie, this volume). It currently this research. The IBISCA-Queensland (Investigating comprises 59,865 hectares and includes extensive Biodiversity of Soil and Canopy Arthro pods) Project areas of rainforest. The name translates as ‘Land of involved a diverse group of about 40 arthropod special- Cloud’, and the area is the traditional home of the ists from 15 countries. Each participant collected data Wirri Aboriginal people (Birri Gubbi Aboriginal on their taxa of choice along the elevational gradient, Corporation, 1996). The rainforests of Eungella are which consisted of 20 sites spanning the full eleva- not included in either of the two rainforest-defined tional distribution of rainforest in the region (Burwell, World Heritage Areas. Nakamura & Kitching, 2011). Over the next five years, Eungella is one of the largest remaining areas comparable surveys were carried out in the nearby of rainforest in Australia and is an intriguing mix Border Ranges National Park, and at Mt Lewis in far of subtropical and tropical elements. The National northern Queensland. Once these surveys were well Park is located on the edge of the Clarke Range, on advanced, it became apparent that the absence of a a plateau including Mt Dalrymple and Mt William. similar survey within the Eungella region – more or Biogeographically, Eungella is bracketed by the Wet less midway between the extensive rainforests of South Tropics in the north and the Lamington/Border Ranges East Queensland and those of the Wet Tropics – rep- (and other) sub-tropical rainforests further south. There resented a major gap in our knowledge of rainforests is, however, no connectivity among these patches, and of Queensland. Funding from the Mackay Regional extended areas of scleromorphic forests occur to both Council allowed this omission to be rectified and the the north and the south. The flora and fauna of Eungella subsequent incorporation of information from Eungella are mixtures of southern and northern elements, and National Park into a larger data-set of elevational gradi- often represents the southernmost or northernmost dis- ents across the eastern coast of Australia (Ashton et al., tribution limits for particular rainforest species. 2016a; Ashton et al., 2016b). Several features make Eungella a particularly The Lamington, Mt Lewis and Eungella studies important area of rainforest. The Eungella rainforests are all predicated on the idea that adjacent elevational are surrounded by the semi-arid Brigalow, and now bands can be used as a surrogate for changes in climate. can be imagined as an island of rainforest surrounded Along an elevational gradient, a 200 m increase in by eucalypt woodlands, cattle grazing and sugar cane eleva tion corresponds to an average drop of 1.2°C farming. This isolation may, over evolutionary time, (Strong et al., 2011). The under lying philos ophy of the have produced Eungella’s several well known, endemic project has been that we can only predict the likely species of vertebrates, such as the Eungella honeyeater results of global warming on bio diversity by studying, (Bolemoreus hindwoodi) and the Eungella torrent frog in the here-and-now, how selected groups of animals (Taudactylus eungellensis). and plants have responded to adjacent climates at The forests of Eungella include a steep range from increasing elevation. Further, only by establishing low to high elevations, adding to their vulnerability to baseline data on current elevational distributions will climate change. Mountainous ecosystems are predicted we be able to detect future responses to change. to be particularly sensitive to climate change (Nogués- During the Eungella Biodiversity Study (here after Bravo et al., 2007). Climatically sensitive species are EBS), 20 × 20 m plots were established, ranging from known to be shifting to higher elevations elsewhere 200 m above sea level (asl). The approach of this study (Chen et al., 2011). Such compensatory shifts, however, was similar to the original IBISCA project, gathering THE EUNGELLA BIODIVERSITY STUDY: FILLING